Merge pull request #1010 from kevin-brown/issue_1008

Fixed arguments in assertion

docs/topics/credits.md

@@ -149,6 +149,7 @@ The following people have helped make REST framework great.
 * Matthias Jacob - [cyroxx]
 * Pavel Zinovkin - [pzinovkin]
 * Will Kahn-Greene - [willkg]
+* Kevin Brown - [kevin-brown]
 
 Many thanks to everyone who's contributed to the project.
 
@@ -334,3 +335,4 @@ You can also contact [@_tomchristie][twitter] directly on twitter.
 [cyroxx]: https://github.com/cyroxx
 [pzinovkin]: https://github.com/pzinovkin
 [willkg]: https://github.com/willkg
+[kevin-brown]: https://github.com/kevin-brown

rest_framework/serializers.py

@@ -690,7 +690,7 @@ class ModelSerializer(Serializer):
             assert field_name in ret, \
                 "Noexistant field '%s' specified in `read_only_fields` " \
                 "on serializer '%s'." % \
-                (self.__class__.__name__, field_name)
+                (field_name, self.__class__.__name__)
             ret[field_name].read_only = True
 
         return ret